Which is better mohs or punch bx?

Different goal: Punch biopsy is a simple way to gain a tissue sample of the skin for analysis and determine of whether it is cancerous. Mohs is a way to gradually remove under microscopic control all tissue that is cancerous until a normal margin is reached. These are two different goals and not a question of preference.

Different intention: A punch biopsy is a diagnostic tool to remove a small pice of tissue for analysis so a treatment plan can be created. Mohs surgery is a technique to remove skin cancer.

Different procedures: Punch biopsy is a method to take a tissue sample for diagnosis. Mohs is a procedure involving taking taking sections of the skin involving skin cancer, preparing frozen sections and staining to look under the microscope. It is considered the gold standard for removing skin cancer and most effective treatment.